goiter

A goiter is simply a visibly or palpably enlarged thyroid — a swelling at the front of the neck. It is a sign, not a diagnosis, like a fever: it tells you the gland is enlarged but not why.

Many different processes can produce one. A classic cause is iodine deficiency: short of raw material, the gland is driven by relentless thyroid-stimulating hormone to grow ever larger trying to capture more iodide. Autoimmune disease (both Graves’ and Hashimoto’s), single or multiple nodules, inflammation, pregnancy, and tumors can all enlarge the gland too. A goiter may come with normal, high, or low hormone levels, so function must be assessed separately from size.

Most goiters are harmless and merely cosmetic, but a large one can press on the windpipe or swallowing tube, causing breathing or swallowing trouble or a hoarse voice. Management follows the cause — iodine where it is lacking, treatment of over- or underactivity, and surgery if a goiter is large, compressive, or suspicious for cancer. Universal salt iodization has dramatically reduced endemic goiter worldwide.